Solid ink compositions comprising crystalline esters of tartaric acid

ABSTRACT

A solid ink composition comprising an amorphous component, a crystalline component, and optionally, a colorant, which are suitable for ink jet printing, including printing on coated paper substrates. In embodiments, the crystalline component is synthesized from an esterification reaction of tartaric acid.

CROSS REFERENCE TO RELATED APPLICATIONS

Reference is made to commonly owned and co-pending, U.S. patentapplication Ser. No. 13/095,784 entitled “Solid Ink CompositionsComprising Amorphous Esters of Tartaric Acid” to Kentaro Morimitsu etal., electronically filed on the same day herewith; U.S. patentapplication Ser. No. 13/095,636 entitled “Solid Ink CompositionsComprising Crystalline-Amorphous Mixtures” to Jennifer Belelie et al.,electronically filed on the same day herewith; U.S. patent applicationSer. No. 13/095,770 entitled “Phase Change Inks and Methods of Makingthe Same” to Kentaro Morimitsu et al., electronically filed on the sameday herewith; U.S. patent application Ser. No. 13/095,591 entitled“Phase Change Ink Components and Methods of Making the Same” to JenniferBelelie et al., electronically filed on the same day herewith; U.S.patent application Ser. No. 13/095,555 entitled “Phase Change Inks andMethods of Making the Same” to Naveen Chopra et al., electronicallyfiled on the same day herewith; U.S. patent application Ser. No.13/095,681 entitled “Solid Ink Compositions ComprisingCrystalline-Amorphous Mixtures” to Jennifer Belelie et al.,electronically filed on the same day herewith; U.S. Pat. No. 8,287,632entitled “Solid Ink Compositions Comprising Amorphous Esters of CitricAcid” to Kentaro Morimitsu et al., electronically filed on the same dayherewith; U.S. patent application Ser. No. 13/095,038 entitled “PrintProcess for Phase Separation Ink” to Paul McConville et al.,electronically filed on the same day herewith; U.S. patent applicationSer. No. 13/095,015 entitled “Solventless Reaction Process” to ThomasEdward Enright et al., electronically filed on the same day herewith;U.S. patent application Ser. No. 13/095,028 entitled “Phase Change Ink”to Kentaro Morimitsu et al., electronically filed on the same dayherewith; U.S. patent application Ser. No. 13/095,174 entitled“Next-Generation Solid Inks From Novel Oxazoline Components, Developedfor Robust Direct-to-Paper Printing” to Rina Carlini et al.,electronically filed on the same day herewith; U.S. patent applicationSer. No. 13/095,221 entitled “Novel Components for a Next-GenerationRobust Solid Ink” to Rina Carlini et al., electronically filed on thesame day herewith; and U.S. patent application Ser. No. 13/095,043entitled “Phase Separation Ink” to Peter G. Odell et al., electronicallyfiled on the same day herewith, the entire disclosures of which areincorporated herein by reference in its entirety.

BACKGROUND

The present embodiments relate to solid ink compositions characterizedby being solid at room temperature and molten, at an elevatedtemperature at which the molten ink is applied to a substrate. Thesesolid ink compositions can be used for ink jet printing. The presentembodiments are directed to a novel solid ink composition comprising anamorphous component, a crystalline component, and optionally a colorant,and methods of making the same.

Ink jet printing processes may employ inks that are solid at roomtemperature and liquid at elevated temperatures. Such inks may bereferred to as solid inks, hot melt inks, phase change inks and thelike. For example, U.S. Pat. No. 4,490,731, the disclosure of which istotally incorporated herein by reference, discloses an apparatus fordispensing solid ink for printing on a recording medium such as paper.In thermal ink jet printing processes employing hot melt inks, the solidink is melted by the heater in the printing apparatus and utilized(jetted) as a liquid in a manner similar to that of conventional thermalink jet printing. Upon contact with the printing recording medium, themolten ink solidifies rapidly, enabling the colorant to substantiallyremain on the surface of the recording medium instead of being carriedinto the recording medium (for example, paper) by capillary action,thereby enabling higher print density than is generally obtained withliquid inks. Advantages of a phase change ink in ink jet printing arethus elimination of potential spillage of the ink during handling, awide range of print density and quality, minimal paper cockle ordistortion, and enablement of indefinite periods of nonprinting withoutthe danger of nozzle clogging, even without capping the nozzles.

In general, phase change inks (sometimes referred to as “hot melt inks”)are in the solid phase at ambient temperature, but exist in the liquidphase at the elevated operating temperature of an ink jet printingdevice. At the jetting temperature, droplets of liquid ink are ejectedfrom the printing device and, when the ink droplets contact the surfaceof the recording medium, either directly or via an intermediate heatedtransfer belt or drum, they quickly solidify to form a predeterminedpattern of solidified ink drops.

Phase change inks for color printing typically comprise a phase changeink carrier composition which is combined with a phase change inkcompatible colorant. In a specific embodiment, a series of colored phasechange inks can be formed by combining ink carrier compositions withcompatible subtractive primary colorants. The subtractive primarycolored phase change inks can comprise four component dyes or pigments,namely, cyan, magenta, yellow and black, although the inks are notlimited to these four colors. These subtractive primary colored inks canbe formed by using a single dye or pigment or a mixture of dyes orpigments. For example, magenta can be obtained by using a mixture ofSolvent Red Dyes or a composite black can be obtained by mixing severaldyes. U.S. Pat. No. 4,889,560, U.S. Pat. No. 4,889,761, and U.S. Pat.No. 5,372,852, the disclosures of each of which are totally incorporatedherein by reference, teach that the subtractive primary colorantsemployed can comprise dyes from the classes of Color Index (C.I.)Solvent Dyes, Disperse Dyes, modified Acid and Direct Dyes, and BasicDyes. The colorants can also include pigments, as disclosed in, forexample, U.S. Pat. No. 5,221,335, the disclosure of which is totallyincorporated herein by reference. U.S. Pat. No. 5,621,022, thedisclosure of which is totally incorporated herein by reference,discloses the use of a specific class of polymeric dyes in phase changeink compositions.

Phase change inks are desirable for ink jet printers because they remainin a solid phase at room temperature during shipping, long term storage,and the like. In addition, the problems associated with nozzle cloggingas a result of ink evaporation with liquid ink jet inks are largelyeliminated, thereby improving the reliability of the ink jet printing.Further, in phase change ink jet printers wherein the ink droplets areapplied directly onto the final recording medium (for example, paper,transparency material, and the like), the droplets solidify immediatelyupon contact with the recording medium, so that migration of ink alongthe printing medium is prevented and dot quality is improved.

While the above conventional solid ink technology is generallysuccessful in producing vivid images and providing economy of jet useand substrate latitude on porous papers, such technology has not beensatisfactory for coated substrates. Thus, while known compositions andprocesses are suitable for their intended purposes, a need remains foradditional means for forming images or printing on coated papersubstrates. As such, there is a need to find alternative compositionsfor solid ink compositions and future printing technologies to providecustomers with excellent image quality on all substrates.

Each of the foregoing U.S. Patents and Patent Publications areincorporated by reference herein. Further, the appropriate componentsand process aspects of the each of the foregoing U.S. Patents and PatentPublications may be selected for the present disclosure in embodimentsthereof.

SUMMARY

According to embodiments illustrated herein, there is provided novelsolid ink compositions comprising crystalline components synthesizedfrom tartaric acid suitable for ink jet printing, including printing oncoated paper substrates.

In particular, the present embodiments provide a phase change inkcomprising: an amorphous component; and a crystalline component, whereinthe crystalline component is an ester of tartaric acid having a formulaof

wherein R¹ and R² each, independently of the other or meaning that theycan be the same or different, is selected from the group consisting ofalkyl group, wherein the alkyl portion can be straight, branched orcyclic, saturated or unsaturated, substituted or unsubstituted, havingfrom about 1 to about 40 carbon atoms, or an substituted orunsubstituted aromatic or heteroaromatic group, and mixtures thereof,and further wherein the tartaric acid backbone is selected fromL-(+)-tartaric acid, D-(−)-tartaric acid, DL-tartaric acid, ormesotartaric acid, and mixtures thereof.

In further embodiments, there is provided a phase change ink comprising:an amorphous component; and a crystalline component, wherein thecrystalline component is an ester of tartaric acid having a formula of

wherein R¹—OH and R²—OH each, independently of the other or meaning thatthey can be the same or different, is selected from the group consistingof

and mixtures thereof, and wherein the tartaric acid backbone is selectedfrom L-(+)-tartaric acid, D-(−)-tartaric acid, DL-tartaric acid, ormesotartaric acid, and mixtures thereof, and further wherein thecrystalline and amorphous components are blended in a weight ratio offrom about 1.5 to about 20.

In yet other embodiments, there is provided a phase change inkcomprising: an amorphous component; and a crystalline component, whereinthe crystalline component is an ester of tartaric acid synthesized by anesterification reaction with at least one alcohol.

BRIEF DESCRIPTION OF THE DRAWINGS

For a better understanding of the present embodiments, reference may behad to the accompanying figures.

FIG. 1 is differential scanning calorimetry (DSC) data of diphenethylL-tartrate (DPT) confirming crystalline properties according to thepresent embodiments (the DSC data was obtained on a Q1000 DifferentialScanning Calorimeter (TA Instruments) at a rate of 10° C./min from −50to 200 to −50° C.);

FIG. 2 is DSC data of diphenethyl L-tartrate (DPT)/di-L-menthylL-tartrate (70/30 weight percent) confirming crystalline propertiesaccording to the present embodiments; and

FIG. 3 is a graph illustrating rheology data of DPT/di-L-menthylL-tartrate (70/30 weight percent) according to the present embodiments.

All of the rheology measurements were made on a RFS3 controlled strainRheometer (TA instruments) equipped with a Peltier heating plate andusing a 25 mm parallel plate. The method used was a temperature sweepfrom high to low temperatures, in temperature decrements of 5° C., asoak (equilibration) time of 120 seconds between each temperature and ata constant frequency of 1 Hz.

DETAILED DESCRIPTION

In the following description, it is understood that other embodimentsmay be utilized and structural and operational changes may be madewithout departure from the scope of the present embodiments disclosedherein.

Solid ink technology broadens printing capability and customer baseacross many markets, and the diversity of printing applications will befacilitated by effective integration of printhead technology, printprocess and ink materials. The solid ink compositions are characterizedby being solid at room temperature (e.g., 20-27° C.) and molten at anelevated temperature at which the molten ink is applied to a substrate.As discussed above, while current ink options are successful for porouspaper substrates, these options are not always satisfactory for coatedpaper substrates.

It has been discovered that using a mixture of crystalline and amorphouscomponents in solid ink formulations provides robust inks, and inparticular, solid inks which demonstrate robust images on uncoated andcoated paper. For crystalline components, small molecules generally tendto crystallize when solidifying and low molecular weight organic solidsare generally crystals. While crystalline components are generallyharder and more resistant, such materials are also much more brittle, sothat printed matter made using a mainly crystalline ink composition isfairly sensitive to damage. For amorphous components, high molecularweight amorphous components, such as polymers, become viscous and stickyliquids at high temperature, but do not show sufficiently low viscosityat high temperatures. As a result, the polymers cannot be jetted fromprint head nozzles at desirable jetting temperature (≦140° C.). In thepresent embodiments, however, it is discovered that a robust solid inkcan be obtained through a blend of crystalline and amorphous components.

The present embodiments provide a new type of ink jet solid inkcomposition which comprises a blend of (1) crystalline and (2) amorphouscomponents, generally in a weight ratio of from about 60:40 to about95:5, respectively. In more specific embodiments, the weight ratio ofthe crystalline to amorphous component is from about 65:35 to about95:5, or is from about 70:30 to about 90:10. In other embodiments, thecrystalline and amorphous components are blended in a weight ratio offrom about 1.5 to about 20 or from about 2.0 to about 10, respectively.Generally, the crystalline and amorphous components are esters oftartaric acid having the formula:

wherein R¹ and R² each, independently of the other or meaning that theycan be the same or different, is selected from the group consisting ofalkyl group, wherein the alkyl portion can be straight, branched orcyclic, saturated or unsaturated, substituted or unsubstituted, havingfrom about 1 to about 40 carbon atoms, or an substituted orunsubstituted aromatic or heteroaromatic group, and mixtures thereof.The tartaric acid backbone is selected from L-(+)-tartaric acid,D-(−)-tartaric acid, DL-tartaric acid, or mesotartaric acid, andmixtures thereof. Depending on the R groups and the stereochemistries oftartaric acid, the esters could form crystals or stable amorphouscompounds.

In specific embodiments, the crystalline component is selected from thegroup consisting of dibenzyl L-tartrate, diphenethyl L-tartrate (DPT),bis(3-phenyl-1-propyl)L-tartrate, bis(2-phenoxyethyl)L-tartrate,diphenyl L-tartrate, bis(4-methylphenyl)L-tartrate,bis(4-methoxylphenyl)L-tartrate, bis(4-methylbenzyl)L-tartrate,bis(4-methoxylbenzyl)L-tartrate, dicyclohexyl L-tartrate,bis(4-tert-butylcyclohexyl)L-tartrate, and any stereoisomers andmixtures thereof. In specific embodiments, the amorphous component isselected from the group consisting of di-L-menthyl L-tartrate,di-DL-menthyl L-tartrate, di-L-menthyl DL-tartrate, di-DL-menthylDL-tartrate, and any stereoisomers and mixtures thereof. Each componentimparts specific properties to the solid inks, and the blend of thecomponents provide inks that exhibit excellent robustness on uncoatedand coated substrates. The crystalline component in the ink formulationdrives the phase change through rapid crystallization on cooling. Thecrystalline component also sets up the structure of the final ink filmand creates a hard ink by reducing the tackiness of the amorphouscomponent. The amorphous components provide tackiness and impartrobustness to the printed ink.

The present embodiments provide crystalline components which aresuitable for solid ink. The crystalline components are synthesized by anesterification reaction of tartaric acid. These materials have a meltingtemperature (T_(melt)) of less than 150° C., or from about 65 to about150° C., or from about 66 to about 145° C., a crystallizationtemperature (T_(crys)) of greater than 60° C., or from about 60 to about140° C., or from about 65 to about 120° C. and viscosity at a jettingtemperature (90-150° C.) of less than 10 centipoise (cps), or from about0.5 to about 10 cps, or from about 1 to about 10 cps. At roomtemperature, the suitable materials are in crystalline form and haveviscosity of greater than about 10⁶ cps.

In embodiments, the crystalline components are formulated with anamorphous component to form a solid ink composition. The inkcompositions show good rheological profiles. Imaged samples created bythe solid ink composition on coated paper by K-proof exhibit excellentrobustness.

A K-proofer is a common test fixture in a print shop. In this case theproofer has been modified to heat the printing plate to melt the solidink. The K-Proofer used has three rectangular gravure patterns eachapproximately 9.4×4.7 cm. The cell density of the first rectangle isnominally 100%, the second 80%, and the third 60%. In practice thisK-proof plate results in films (or pixels) of about 5 microns inthickness (or height). Test ink is spread over the heated gravure plateand a test print is made by passing a wiping blade across the platesurface immediately follow by a rubber roll upon which a test paper hasbeen secured. As the paper roll passes, ink is transferred from thegravure cells to the paper. Furthermore, using tartaric acid as an esterbase has additional advantages of being low cost, and being obtainedfrom a potential bio-derived (“green”) source.

In embodiments, the solid ink composition is obtained by using novelcrystalline components synthesized from tartaric acid and at least onealcohol in an esterification reaction. The solid ink compositioncomprises the crystalline component in combination with an amorphouscomponent and a colorant. The present embodiments comprise a balance ofamorphous and crystalline components to realize a sharp phase transitionfrom liquid to solid and facilitate hard and robust printed images,while maintaining a desired level of viscosity. Prints made with thisink demonstrated advantages over commercially available inks, such asfor example, better robustness against scratch. Thus, the present estersof tartaric acid, which provide crystalline components for the solidinks, have been discovered to produce robust inks having desirablerheological profiles and that meet the many requirements for inkjetprinting.

The ink composition, in specific embodiments, further comprises acolorant, which may be a pigment or dye, present in the ink compositionin an amount of at least from about 0.1 percent to about 50 percent byweight, or at least from about 0.2 percent to about 20 percent by weightof the total weight of the ink composition. The solid ink compositionalso comprises a crystalline component. The crystalline component ispresent an amount of from about 60 percent to about 95 percent byweight, or from about 65 percent to about 95 percent by weight of thetotal weight of the ink composition. The amorphous component is presentan amount of from about 5 percent to about 40 percent by weight, or fromabout 5 percent to about 35 percent by weight of the total weight of theink composition.

In embodiments, the resulting solid ink has a viscosity of from about 1to about 14 cps, or from about 2 to about 13 cps, or from about 3 toabout 12 cps, at a temperature of about 140° C. In embodiments, thesolid ink has a viscosity of about >10⁶ cps at room temperature. Inembodiments, the solid ink has a T_(melt) of from about 65 to about 140°C., or from about 65 to about 135° C., from about 70 to about 130° C.and a T_(crys) of from about 40 to about 140° C., or from about 45 toabout 130° C., from about 50 to about 125° C., as determined by DSC at arate of 10° C./min.

The ink composition of the present embodiments comprises a crystallinecomponent. Tartaric acid was reacted with a variety of alcohols to makedi-esters as shown in the synthesis scheme below, which illustrates thepreparation of a tartaric acid di-ester compound of the presentembodiments.

The esterification was conducted by a one-step reaction. Out of tendifferent alcohols reacted (benzyl alcohol, phenethyl alcohol,2-phenoxyethanol, 3-phenyl-1-propanol, 4-methylbenzyl alcohol,4-methoxyphenol, cyclohexanol, cyclopentanol, 4-tert-butylcyclohexanol,3,5,5-trimethyl-1-hexanol), phenethyl alcohol was identified as the bestmaterial to form a stable crystalline component with suitable physicalproperties. Di-esters of 3,5,5-trimethyl-1-hexanol and cyclopentanolwere viscous liquids at room temperature and the rest of the synthesizeddi-esters were crystals. Suitable alcohols to be used in theesterification with the present embodiments may be selected from thegroup consisting of alkyl alcohol, wherein the alkyl portion of thealcohol can be straight, branched or cyclic, saturated or unsaturated,substituted or unsubstituted, having from about 1 to about 40 carbonatoms, or an substituted or unsubstituted aromatic or heteroaromaticgroup, and mixtures thereof. In embodiments, two or more molarequivalents of alcohol may be used in the reaction to produce thedi-esters of tartaric acid. If one molar equivalent of alcohol is used,the result is mostly mono-esters.

In FIG. 1, differential scanning calorimetry (DSC, 10° C./min from −50to 200 to −50° C.) data of diphenethyl L-tartrate (DPT) showed verysharp phase transitions indicating melting temperature (T_(melt)) of110° C. and crystallization temperature (T_(crys)) of 83° C., which areboth in desirable ranges for the phase changing material of the ink. Therelatively narrow gap between T_(melt) and T_(cryst) translates to arapid phase change, making this material an especially good candidatefor the crystalline component of the ink.

Viscosity of DPT was measured to be 4.7 cps at 140° C. and 10.3 cps at110° C. The low viscosity in the jetting range of 100-140° C. provideshigh formulation latitude. Although the rheometer cannot determine theviscosity at room temperature because DPT is solid crystalline state(η>10⁶ cps), the crystallinity is desirable to impart hardness. Thesecharacteristics make the identified materials good candidates for thecrystalline component.

The ink of embodiments may further include conventional additives totake advantage of the known functionality associated with suchconventional additives. Such additives may include, for example, atleast one antioxidant, defoamer, slip and leveling agents, clarifier,viscosity modifier, adhesive, plasticizer and the like.

The ink may optionally contain antioxidants to protect the images fromoxidation and also may protect the ink components from oxidation whileexisting as a heated melt in the ink reservoir. Examples of suitableantioxidants include (1) N,N′-hexamethylenebis(3,5-di-tert-butyl-4-hydroxy hydrocinnamamide) (IRGANOX 1098,available from BASF), (2)2,2-bis(4-(2-(3,5-di-tert-butyl-4-hydroxyhydrocinnamoyloxy))ethoxyphenyl)propane(TOPANOL-205, available from Vertellus), (3)tris(4-tert-butyl-3-hydroxy-2,6-dimethyl benzyl)isocyanurate (AldrichD12,840-6), (4) 2,2′-ethylidene bis(4,6-di-tert-butylphenyl)fluorophosphonite (ETHANOX-398, available from Albermarle Corporation), (5)tetrakis(2,4-di-tert-butylphenyl)-4,4′-biphenyl diphosphonite (ALDRICH46,852-5), (6) pentaerythritol tetrastearate (TCI America), (7)tributylammonium hypophosphite (Aldrich 42,009-3), (8)2,6-di-tert-butyl-4-methoxyphenol (Aldrich 25,106-2), (9)2,4-di-tert-butyl-6-(4-methoxybenzyl)phenol (Aldrich 23,008-1), (10)4-bromo-2,6-dimethylphenol (Aldrich 34,951-8), (11)4-bromo-3,5-didimethylphenol (Aldrich B6,420-2), (12)4-bromo-2-nitrophenol (Aldrich 30,987-7), (13) 4-(diethylaminomethyl)-2,5-dimethylphenol (Aldrich 14,668-4), (14)3-dimethylaminophenol (Aldrich 1014,400-2), (15)2-amino-4-tert-amylphenol (Aldrich 41,258-9), (16)2,6-bis(hydroxymethyl)-p-cresol (Aldrich 22,752-8), (17)2,2′-methylenediphenol (Aldrich B4,680-8), (18)5-(diethylamino)-2-nitrosophenol (Aldrich 26,951-4), (19)2,6-dichloro-4-fluorophenol (Aldrich 28,435-1), (20) 2,6-dibromo fluorophenol (Aldrich 26,003-7), (21) α-trifluoro-o-creso-1 (Aldrich21,979-7), (22) 2-bromo-4-fluorophenol (Aldrich 30,246-5), (23)4-fluorophenol (Aldrich F1,320-7), (24)4-chlorophenyl-2-chloro-1,1,2-tri-fluoroethyl sulfone (Aldrich13,823-1), (25) 3,4-difluoro phenylacetic acid (Aldrich 29,043-2), (26)3-fluorophenylacetic acid (Aldrich 24,804-5), (27) 3,5-difluorophenylacetic acid (Aldrich 29,044-0), (28) 2-fluorophenylacetic acid(Aldrich 20,894-9), (29) 2,5-bis (trifluoromethyl) benzoic acid (Aldrich32,527-9), (30)ethyl-2-(4-(4-(trifluoromethyl)phenoxy)phenoxy)propionate (Aldrich25,074-0), (31) tetrakis (2,4-di-tert-butyl phenyl)-4,4′-biphenyldiphosphonite (Aldrich 46,852-5), (32) 4-tert-amyl phenol (Aldrich15,384-2), (33) 3-(2H-benzotriazol-2-yl)-4-hydroxy phenethylalcohol(Aldrich 43,071-4), NAUGARD 76, NAUGARD 445, NAUGARD 512, AND NAUGARD524 (manufactured by Chemtura Corporation), and the like, as well asmixtures thereof. The antioxidant, when present, may be present in theink in any desired or effective amount, such as from about 0.25 percentto about 10 percent by weight of the ink or from about 1 percent toabout 5 percent by weight of the ink.

In embodiments, the phase change ink compositions described herein alsoinclude a colorant. The ink of the present embodiments can thus be onewith or without colorants. Any desired or effective colorant can beemployed in the phase change ink compositions, including dyes, pigments,mixtures thereof, and the like, provided that the colorant can bedissolved or dispersed in the ink carrier. Any dye or pigment may bechosen, provided that it is capable of being dispersed or dissolved inthe ink carrier and is compatible with the other ink components. Thephase change carrier compositions can be used in combination withconventional phase change ink colorant materials, such as Color Index(C.I.) Solvent Dyes, Disperse Dyes, modified Acid and Direct Dyes, BasicDyes, Sulphur Dyes, Vat Dyes, and the like. Examples of suitable dyesinclude Neozapon Red 492 (BASF); Orasol Red G (Pylam Products); DirectBrilliant Pink B (Oriental Giant Dyes); Direct Red 3BL (ClassicDyestuffs); Supranol Brilliant Red 3BW (Bayer AG); Lemon Yellow 6G(United Chemie); Light Fast Yellow 3G (Shaanxi); Aizen Spilon YellowC-GNH (Hodogaya Chemical); Bemachrome Yellow GD Sub (Classic Dyestuffs);Cartasol Brilliant Yellow 4GF (Clariant); Cibanone Yellow 2G (ClassicDyestuffs); Orasol Black RLI (BASF); Savinyl Black RLSN (Clariant);Pyrazol Black BG (Clariant); Morfast Black 101 (Rohm & Haas); DiaazolBlack RN (ICI); Thermoplast Blue 670 (BASF); Orasol Blue GN (PylamProducts); Savinyl Blue GLS (Clariant); Luxol Fast Blue MBSN (PylamProducts); Sevron Blue 5GMF (Classic Dyestuffs); Basacid Blue 750(BASF); Keyplast Blue (Keystone Aniline Corporation); Neozapon Black X51(BASF); Classic Solvent Black 7 (Classic Dyestuffs); Sudan Blue 670(C.I. 61554) (BASF); Sudan Yellow 146 (C.I. 12700) (BASF); Sudan Red 462(C.I. 26050) (BASF); C.I. Disperse Yellow 238; Neptune Red Base NB543(BASF, C.I. Solvent Red 49); Neopen Blue FF-4012; (BASF); LampronolBlack BR (C.I. Solvent Black 35) (ICI); Morton Morplas Magenta 36 (C.I.Solvent Red 172); metal phthalocyanine colorants such as those disclosedin U.S. Pat. No. 6,221,137, the disclosure of which is totallyincorporated herein by reference, and the like. Polymeric dyes can alsobe used, such as those disclosed in, for example, U.S. Pat. No.5,621,022 and U.S. Pat. No. 5,231,135, the disclosures of each of whichare herein entirely incorporated herein by reference, and commerciallyavailable from, for example, Milliken & Company as Milliken Ink Yellow869, Milliken Ink Blue 92, Milliken Ink Red 357, Milliken Ink Yellow1800, Milliken Ink Black 8915-67, uncut Reactint Orange X-38, uncutReactint Blue X-17, Solvent Yellow 162, Acid Red 52, Solvent Blue 44,and uncut Reactint Violet X-80.

Pigments are also suitable colorants for the phase change inks. Examplesof suitable pigments include PALIOGEN Violet 5100 (BASF); PALIOGENViolet 5890 (BASF); HELIOGEN Green L8730 (BASF); LITHOL Scarlet D3700(BASF); SUNFAST Blue 15:4 (Sun Chemical); Hostaperm Blue B2G-D(Clariant); Hostaperm Blue B4G (Clariant); Permanent Red P-F7RK;Hostaperm Violet BL (Clariant); LITHOL Scarlet 4440 (BASF); Bon Red C(Dominion Color Company); ORACET Pink RF (BASF); PALIOGEN Red 3871 K(BASF); SUNFAST Blue 15:3 (Sun Chemical); PALIOGEN Red 3340 (BASF);SUNFAST Carbazole Violet 23 (Sun Chemical); LITHOL Fast Scarlet L4300(BASF); SUNBRITE Yellow 17 (Sun Chemical); HELIOGEN Blue L6900, L7020(BASF); SUNBRITE Yellow 74 (Sun Chemical); SPECTRA PAC C Orange 16 (SunChemical); HELIOGEN Blue K6902₇, K6910 (BASF); SUNFAST Magenta 122 (SunChemical); HELIOGEN Blue D6840, D7080 (BASF); Sudan Blue OS (BASF);NEOPEN Blue FF4012 (BASF); PV Fast Blue B2GO1 (Clariant); IRGALITE BlueGLO (BASF); PALIOGEN Blue 6470 (BASF); Sudan Orange G (Aldrich), SudanOrange 220 (BASF); PALIOGEN Orange 3040 (BASF); PALIOGEN Yellow 152,1560 (BASF); LITHOL Fast Yellow 0991 K (BASF); PALIOTOL Yellow 1840(BASF); NOVOPERM Yellow FGL (Clariant); Ink Jet Yellow 4G VP2532(Clariant); Toner Yellow HG (Clariant); Lumogen Yellow 00790 (BASF);Suco-Yellow L1250 (BASF); Suco-Yellow D1355 (BASF); Suco Fast YellowD1355, D1351 (BASF); HOSTAPERM Pink E 02 (Clariant); Hansa BrilliantYellow 5GX03 (Clariant); Permanent Yellow GRL 02 (Clariant); PermanentRubine L6B 05 (Clariant); FANAL Pink 04830 (BASF); CINQUASIA Magenta (DUPONT); PALIOGEN Black L0084 (BASF); Pigment Black K801 (BASF); andcarbon blacks such as REGAL 330™ (Cabot), Nipex 150 (Evonik) CarbonBlack 5250 and Carbon Black 5750 (Columbia Chemical), and the like, aswell as mixtures thereof.

Pigment dispersions in the ink base may be stabilized by synergists anddispersants. Generally, suitable pigments may be organic materials orinorganic. Magnetic material-based pigments are also suitable, forexample, for the fabrication of robust Magnetic Ink CharacterRecognition (MICR) inks. Magnetic pigments include magneticnanoparticles, such as for example, ferromagnetic nanoparticles.

Also suitable are the colorants disclosed in U.S. Pat. No. 6,472,523,U.S. Pat. No. 6,726,755, U.S. Pat. No. 6,476,219, U.S. Pat. No.6,576,747, U.S. Pat. No. 6,713,614, U.S. Pat. No. 6,663,703, U.S. Pat.No. 6,755,902, U.S. Pat. No. 6,590,082, U.S. Pat. No. 6,696,552, U.S.Pat. No. 6,576,748, U.S. Pat. No. 6,646,111, U.S. Pat. No. 6,673,139,U.S. Pat. No. 6,958,406, U.S. Pat. No. 6,821,327, U.S. Pat. No.7,053,227, U.S. Pat. No. 7,381,831 and U.S. Pat. No. 7,427,323, thedisclosures of each of which are incorporated herein by reference intheir entirety.

In embodiments, solvent dyes are employed. An example of a solvent dyesuitable for use herein may include spirit soluble dyes because of theircompatibility with the ink carriers disclosed herein. Examples ofsuitable spirit solvent dyes include Neozapon Red 492 (BASF); Orasol RedG (Pylam Products); Direct Brilliant Pink B (Global Colors); AizenSpilon Red C-BH (Hodogaya Chemical); Kayanol Red 3BL (Nippon Kayaku);Spirit Fast Yellow 3G; Aizen Spilon Yellow C-GNH (Hodogaya Chemical);Cartasol Brilliant Yellow 4GF (Clariant); Pergasol Yellow % RA EX(Classic Dyestuffs); Orasol Black RLI (BASF); Orasol Blue GN (PylamProducts); Savinyl Black RLS (Clariant); Morfast Black 101 (Rohm andHaas); Thermoplast Blue 670 (BASF); Savinyl Blue GLS (Sandoz); LuxolFast Blue MBSN (Pylam); Sevron Blue 5GMF (Classic Dyestuffs); BasacidBlue 750 (BASF); Keyplast Blue (Keystone Aniline Corporation); NeozaponBlack X51 (C.I. Solvent Black, C.I. 12195) (BASF); Sudan Blue 670 (C.I.61554) (BASF); Sudan Yellow 146 (C.I. 12700) (BASF); Sudan Red 462 (C.I.260501) (BASF), mixtures thereof and the like.

The colorant may be present in the phase change ink in any desired oreffective amount to obtain the desired color or hue such as, forexample, at least from about 0.1 percent by weight of the ink to about50 percent by weight of the ink, at least from about 0.2 percent byweight of the ink to about 20 percent by weight of the ink, and at leastfrom about 0.5 percent by weight of the ink to about 10 percent byweight of the ink.

In embodiments, the ink carriers for the phase change inks may havemelting points of from about 65° C. to about 150° C., for example fromabout 70° C. to about 140° C., from about 75° C. to about 135° C., fromabout 80° C. to about 130° C., or from about 85° C. to about 125° C. asdetermined by, for example, differential scanning calorimetry at a rateof 10° C./min. Furthermore, these inks have a jetting viscosity of about1 cps to about 13 cps, such as from about 2 cps to about 13 cps, fromabout 4 cps to about 12 cps, at temperature of about 140° C.

The ink compositions can be prepared by any desired or suitable method.For example, each of the components of the ink carrier can be mixedtogether, followed by heating, the mixture to at least its meltingpoint, for example from about 60° C. to about 150° C., 80° C. to about145° C. and 85° C. to about 140° C. The colorant may be added before theink ingredients have been heated or after the ink ingredients have beenheated. When pigments are the selected colorants, the molten mixture maybe subjected to grinding in an attritor or ball mill apparatus or otherhigh energy mixing equipment to affect dispersion of the pigment in theink carrier. The heated mixture is then stirred for about 5 seconds toabout 30 minutes or more, to obtain a substantially homogeneous, uniformmelt, followed by cooling the ink to ambient temperature (typically fromabout 20° C. to about 25° C.). The inks are solid at ambienttemperature. In a specific embodiment, during the formation process, theinks in their molten state are poured into molds and then allowed tocool and solidify to form ink sticks. Suitable ink preparationtechniques are disclosed in U.S. Pat. No. 7,186,762, the disclosure ofwhich is incorporated herein by reference in its entirety.

The inks can be employed in apparatus for direct printing ink jetprocesses and in indirect (offset) printing ink jet applications.Another embodiment disclosed herein is directed to a process whichcomprises incorporating an ink as disclosed herein into an ink jetprinting apparatus, melting the ink, and causing droplets of the meltedink to be ejected in an imagewise pattern onto a recording substrate. Adirect printing process is also disclosed in, for example, U.S. Pat. No.5,195,430, the disclosure of which is totally incorporated herein byreference. Yet another embodiment disclosed herein is directed to aprocess which comprises incorporating an ink as disclosed herein into anink jet printing apparatus, melting the ink, causing droplets of themelted ink to be ejected in an imagewise pattern onto an intermediatetransfer member, and transferring the ink in the imagewise pattern fromthe intermediate transfer member to a final recording substrate. In aspecific embodiment, the intermediate transfer member is heated to atemperature above that of the final recording sheet and below that ofthe melted ink in the printing apparatus. In another specificembodiment, both the intermediate transfer member and the finalrecording sheet are heated; in this embodiment, both the intermediatetransfer member and the final recording sheet are heated to atemperature below that of the melted ink in the printing apparatus; inthis embodiment, the relative temperatures of the intermediate transfermember and the final recording sheet can be (1) the intermediatetransfer member is heated to a temperature above that of the finalrecording substrate and below that of the melted ink in the printingapparatus; (2) the final recording substrate is heated to a temperatureabove that of the intermediate transfer member and below that of themelted ink in the printing apparatus; or (3) the intermediate transfermember and the final recording sheet are heated to approximately thesame temperature. An offset or indirect printing process is alsodisclosed in, for example, U.S. Pat. No. 5,389,958, the disclosure ofwhich is totally incorporated herein by reference. In one specificembodiment, the printing apparatus employs a piezoelectric printingprocess wherein droplets of the ink are caused to be ejected inimagewise pattern by oscillations of piezoelectric vibrating elements.Inks as disclosed herein can also be employed in other hot melt printingprocesses, such as hot melt acoustic ink jet printing, hot melt thermalink jet printing, hot melt continuous stream or deflection ink jetprinting, and the like. Phase change inks as disclosed herein can alsobe used in printing processes other than hot melt ink jet printingprocesses.

Any suitable substrate or recording sheet can be employed, includingplain papers such as XEROX 4200 papers, XEROX Image Series papers,Courtland 4024 DP paper, ruled notebook paper, bond paper, silica coatedpapers such as Sharp Company silica coated paper, JuJo paper, HAMMERMILLLASERPRINT paper, and the like, glossy coated papers such as XEROXDigital Color Elite Gloss, Sappi Warren Papers LUSTROGLOSS, specialtypapers such as Xerox DURAPAPER, and the like, transparency materials,fabrics, textile products, plastics, polymeric films, inorganicrecording mediums such as metals and wood, and the like, transparencymaterials, fabrics, textile products, plastics, polymeric films,inorganic substrates such as metals and wood, and the like.

The inks described herein are further illustrated in the followingexamples. All parts and percentages are by weight unless otherwiseindicated.

It will be appreciated that various of the above-disclosed and otherfeatures and functions, or alternatives thereof, may be desirablycombined into many other different systems or applications. Also,various presently unforeseen or unanticipated alternatives,modifications, variations or improvements therein may be subsequentlymade by those skilled in the art, and are also intended to beencompassed by the following claims.

While the description above refers to particular embodiments, it will beunderstood that many modifications may be made without departing fromthe spirit thereof. The accompanying claims are intended to cover suchmodifications as would fall within the true scope and spirit ofembodiments herein.

The presently disclosed embodiments are, therefore, to be considered inall respects as illustrative and not restrictive, the scope ofembodiments being indicated by the appended claims rather than theforegoing description. All changes that come within the meaning of andrange of equivalency of the claims are intended to be embraced therein.

EXAMPLES

The examples set forth herein below and are illustrative of differentcompositions and conditions that can be used in practicing the presentembodiments. All proportions are by weight unless otherwise indicated.It will be apparent, however, that the present embodiments can bepracticed with many types of compositions and can have many differentuses in accordance with the disclosure above and as pointed outhereinafter.

Example 1

Synthesis of Materials

In a typical synthesis of, for example, diphenethyl L-tartrate (DPT),L-tartaric acid (9.0 g, 60 mmol), phenethyl alcohol (22.0 g, 180 mmol),and toluene (120 ml) were added to a 500 mL flask, equipped with aDean-Stark trap, to give a suspension. p-Toluenesulfonic acidmonohydrate (0.14 g, 0.75 mmol) was added and the mixture was refluxedfor 17 hours with azeotropic removal of water. The reaction mixture wascooled down to room temperature and washed with NaHCO₃ aq. (2×) andbrine (1×), then dried over MgSO₄. After filtration and removal of thesolvent, the residue was recrystallized from toluene to obtain 16.9 g(yield: 79%) of white crystals. The sample was characterized by ¹H NMRand acid number analysis (4.06 mgKOH/g). The synthesis scheme isillustrated below:

Preparation of the Solid Ink

Di-L-menthyl L-tartrate was selected for the amorphous component (η(>100° C.,)<10² cps and η (at room temperature)>10⁶ cps). This materialwas synthesized, as described in U.S. patent application Ser. No.13/095,784 entitled “Solid Ink Compositions Comprising Amorphous Estersof Tartaric Acid” to Kentaro Morimitsu et al., and used as the amorphousportion of the ink. DPT and the amorphous component were stirred in themolten state at 120° C., then cooled down to obtain the ink sample. Thecrystalline/amorphous ratio of the ink sample was 70/30 in weightpercent. The two materials were well miscible in this mixing ratio.

FIG. 2 shows DSC data of the resulting ink. Both T_(melt) and T_(crys)shifted to lower temperatures, but the sample still showed sharp phasetransitions even when mixed with amorphous component. FIG. 3 showsrheology data of the resulting ink. The ink showed phase transition to>10⁶ cps at around 85° C., but the phase transition temperature will beadjustable by changing the crystalline/amorphous ratio. The viscosity ataround 130° C. was below 12 cps.

Print Performance

To the ink sample was further added 3 weight percent of cyan dye (CibaOrasol Blue GN) which showed good solubility in the ink. The ink wassubsequently coated using a K Printing Proofer (manufactured by RK PrintCoat Instrument Ltd., Litlington, Royston, Heris, SG8 0OZ, U.K.) ontoXerox digital Color Elite Gloss, 120 gsm (DCEG). When a scratch/gougefinger with a curved tip at an angle of about 15° from vertical, with aweight of 528 g applied, was drawn across the image at a rate ofapproximately 13 mm/s no ink was visibly removed from the image. Thescratch/gouge tip is similar to a lathe round nose cutting bit withradius of curvature of approximately 12 mm.

Summary

In summary, the present embodiments provide solid ink formulationsdeveloped for inkjet printing which contains at least one crystallinecomponent and at least one amorphous component. The inks may alsoinclude a colorant, such as a pigment or dye. The novel crystallinecomponents are synthesized from tartaric acid and at least one alcohol,such as phenethyl alcohol, by esterification reactions. The resultingcrystalline materials have desirable physical properties which providefor robust inks.

The claims, as originally presented and as they may be amended,encompass variations, alternatives, modifications, improvements,equivalents, and substantial equivalents of the embodiments andteachings disclosed herein, including those that are presentlyunforeseen or unappreciated, and that, for example, may arise fromapplicants/patentees and others. Unless specifically recited in a claim,steps or components of claims should not be implied or imported from thespecification or any other claims as to any particular order, number,position, size, shape, angle, color, or material.

All the patents and applications referred to herein are herebyspecifically, and totally incorporated herein by reference in theirentirety in the instant specification.

What is claimed is:
 1. A phase change ink comprising: at least anamorphous component, wherein the amorphous component is selected fromthe group consisting of di-L-menthyl L-tartrate, di-DL-menthylL-tartrate, di-L-menthyl DL-tartrate, di-DL-menthyl DL-tartrate, and anystereoisomers and mixtures thereof; and at least a crystallinecomponent, wherein the crystalline component is an ester of tartaricacid having a formula of

wherein R¹ and R² each, independently of the other, is selected from thegroup consisting of alkyl group, wherein the alkyl portion can bestraight, branched or cyclic, saturated or unsaturated, substituted orunsubstituted, having from 1 to 40 carbon atoms, or an substituted orunsubstituted aromatic or heteroaromatic group, and mixtures thereof,and further wherein the tartaric acid backbone is selected fromL-(+)-tartaric acid, D-(−)-tartaric acid, DL-tartaric acid, ormesotartaric acid, and mixtures thereof.
 2. The phase change ink ofclaim 1, wherein the amorphous component is present in an amount of from5 percent to 40 percent by weight of the total weight of the phasechange ink.
 3. The phase change ink of claim 2, wherein the amorphouscomponent is present in an amount of from 5 percent to 35 percent byweight of the total weight of the phase change ink.
 4. The phase changeink of claim 1, wherein the crystalline component is present in anamount of from 60 percent to 95 percent by weight of the total weight ofthe phase change ink.
 5. The phase change ink of claim 4, wherein thecrystalline component is present in an amount of from 65 percent to 95percent by weight of the total weight of the phase change ink.
 6. Thephase change ink of claim 1, wherein the crystalline and amorphouscomponents are blended in a range of weight ratios of from 1.5 to
 20. 7.The phase change ink of claim 6, wherein the crystalline and amorphouscomponents are blended in a range of weight ratios of from 2 to
 10. 8.The phase change ink of claim 1, wherein the crystalline component isselected from the group consisting of dibenzyl L-tartrate, diphenethylL-tartrate, bis(3-phenyl-1-propyl) L-tartrate, bis(2-phenoxyethyl)L-tartrate, diphenyl L-tartrate, bis(4-methylphenyl) L-tartrate,bis(4-methoxylphenyl) L-tartrate, bis(4-methylbenzyl) L-tartrate,bis(4-methoxylbenzyl) L-tartrate, dicyclohexyl L-tartrate,bis(4-tert-butylcyclohexyl) L-tartrate, and any stereoisomers andmixtures thereof.
 9. The phase change ink of claim 1 further comprisinga colorant selected from the group consisting of a pigment, dye ormixtures thereof.
 10. The phase change ink of claim 1, wherein thecrystalline component has a viscosity of from 1 to 10 cps at atemperature of 140° C.
 11. The phase change ink of claim 1, wherein thecrystalline component is in crystallized form at room temperature. 12.The phase change ink of claim 1 having a viscosity of less than 15 cpsat a temperature of 140° C.
 13. The phase change ink of claim 12 havinga viscosity of from 2 to 15 cps at a temperature of 140° C.
 14. Thephase change ink of claim 1 having a viscosity of greater than 10⁶ cpsat room temperature.
 15. A phase change ink comprising: an amorphouscomponent, wherein the amorphous component is selected from the groupconsisting of di-L-menthyl L-tartrate, di-DL-menthyl L-tartrate,di-L-menthyl DL-tartrate, di-DL-menthyl DL-tartrate, and anystereoisomers and mixtures thereof; a crystalline component; andoptionally a colorant, wherein the crystalline component is an ester oftartaric acid having a formula of

wherein R¹ and R² each, independently of the other, is selected from thegroup consisting of

and mixtures thereof, and wherein the tartaric acid backbone is selectedfrom L-(+)-tartaric acid, D-(−)-tartaric acid, DL-tartaric acid, ormesotartaric acid, and mixtures thereof, and further wherein thecrystalline and amorphous components are blended in a range of weightratios of from 1.5 to
 20. 16. The phase change ink of claim 15, whereinthe amorphous component is synthesized by an esterification reactionwith at least one alcohol.
 17. The phase change ink of claim 15, whereinthe crystalline and amorphous components are blended in a range ofweight ratios of from 1.5 to
 20. 18. A phase change ink comprising: anamorphous component, wherein the amorphous component is selected fromthe group consisting of di-L-menthyl L-tartrate, di-DL-menthylL-tartrate, di-L-menthyl DL-tartrate, di-DL-menthyl DL-tartrate, and anystereoisomers and mixtures thereof; and a crystalline component, whereinthe crystalline component is an ester of tartaric acid synthesized by anesterification reaction with at least one alcohol.
 19. The phase changeink of claim 18, wherein the alcohol is R—OH being selected from thegroup consisting of

and mixtures thereof.